Plastic can with metal end



Jan. 27, 1970 J. F. FOX

PLASTIC CAN WITH METAL END Filed Dec. 5. 1967 8 m ORNEYS INVENTOR JAME$ F- {FOX United States Fatent O 3,491,936 PLASTIC CAN WITH METAL END James F. Fox, Chicago, Ill., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Dec. 5, 1967, Ser. No. 688,081

Int. Cl. B65d 3/10 US. Cl. 2295.6 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a can which includes a plastic body having a metal end unit. The can is particularly adapted for receiving hams and other irregularly shaped products which are compactly placed within the can and assist in retaining the shape thereof. A particularly important feature of the can is the formation of the upper portion of the body wall of the can body to facilitate the double seaming of the metal end unit thereto. During the double seaming operation, the body is positioned within a mold which is particularly configurated for cooperation with the body to support the same during the double seaming operation.

This invention relates to a can particularly adapted for the packaging of hams and other products which may be compactly packaged within cans with the can being particularly characterized by the body being formed of plastic and having an integral bottom.

Although it has been recognized that plastic bodies having integral bottoms may be readily molded in an economical manner and such bodies may have a highly desirable ornamental appearance, in the past the bodies have not been feasible for the packaging of food products and the like due to difiiculties experienced in securing metal end units thereto in a commercially feasible man ner. However, in accordance with this invention, the upper portion of the body wall of the plastic can body is provided with a radially outwardly directed shoulder which, during the seaming of the metal end unit thereto, is supported by a mold and, in turn, supports the end unit when the end unit is applied by way of axially directed pressure, and it is possible to secure the metal end unit to the plastic body by means of a conventional double seaming operation.

Another feature of this invention is the provision of a mold in which a plastic can body, which may be badly distorted, may be readily positioned, followed by the filling thereof with a ham or other product which is compactly placed therein and which forces the body wall of the can body radially outwardly in accordance with the intended configuration of the can body, as defined by the mold, and the mold having an upper supporting surface supporting the upper portion of the body wall during the securement of a metal end unit thereto.

A further feature of this invention is the provision of a novel method of securing a metal end unit to a plastic can body, the method including the supporting of the upper portion of the plastic body wall against both radial F a 3,491,936 Patented Jan. 27, 1970 and axial movement and thereafter applying the metal end unit to the plastic body under axially directed pressure to initially seat the end unit on the plastic body wall and thereafter secure the end unit to the body wall by means of a conventional type of double seaming operation.

With the above and other objects in View that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing:

In the drawing:

FIGURE 1 is a top perspective view of a plastic can body formed in accordance with this invention.

FIGURE 2 is an exploded vertical sectional view taken through apparatus for closing the can body of FIGURE 1 utilizing a metal end and shows the can body and end unit generally in position.

FIGURE 3 is an enlarged fragmentary vertical sectional view taken through the upper portion of the can body and shows generally the initial relationship thereof with respect to a supporting mold.

FIGURE 4 is a sectional view similar to FIGURE 3 and shows the can body after the initial positioning of the metal end unit thereon.

FIGURE 5 is a fragmentary vertical sectional view showing the manner in which the upper portion of the plastic body wall is supported by the mold and the end unit is, in turn, supported by the body wall.

FIGURE 6 is a fragmentary vertical sectional view taken through the same portion of the can after a first seaming operation.

FIGURE 7 is a vertical sectional view similar to FIG- URE 6 and shows the final seam configuration.

Referring now to the drawings in detail, it will be seen that there is illustrated in FIGURE 1 a plastic can body formed in accordance with this invention, the can body being generally referred to by the numeral 10. The illustrated can body is of a configuration particularly adapted to receive a ham and while this is the primary intended use of the can bodies formed in accordance with this invention, it is to be understood that the can body 10 may be of any configuration required for a particular product being packaged.

The can body 10 is of a one-piece molded construction and includes a bottom wall 11 and an upstanding body Wall 12. As is best shown in FIGURE 2, the body wall 12 is upwardly flared from the bottom wall 11. This both facilitates the handling of the can body 10 in a manner to be described hereinafter, and the removal of a product therefrom.

Referring now to FIGURE 3 in particular, it will be seen that the body wall 12 includes an upper seam forming portion 13 which is of a reduced thickness as compared to the remainder of the body wall and terminates at the free end thereof in a radially outwardly directed flange 14 which is further reduced in thickness and is about one half the thickness of the main portion of the body wall. The seam forming portion 13 is radially outwardly offset relative to the adjacent portion of the body wall 12 and is connected thereto by an intermediate shoulder 15. The shoulder 15 has a rounded outer seat forming surface 16 and a generally flat inner supporting surface 17. It is further to be noted that the intermediate shoulder 15 tapers so as to merge the thicker body wall 12 into the thinner seam forming portion 13.

In accordance with this invention, it is proposed to close the open upper end of the can body 10 with a metal end unit which is generally referred to by the numeral 18. The end unit 18, as is best shown in FIGURE 4, includes an end panel 20 which is surrounded by a downwardly directed bead 21. The bead 21 forms a lower extension of the usual chuck wall 22 which surrounds the end panel 20. The usual chuck Wall radius 23 forms a part of the bead 21. The end unit 18 also includes the usual seaming panel 24 which terminates at its free end in a curl 25. The seaming panel 24 is connected to the chuck wall 22 by means of a seaming panel radius 26.

At this time it is pointed out that in order to assure a proper seal between the end unit 18 and the can body 10, there is applied to the end unit 18 a sealing compound 27. It is to be noted from FIGURE 4 that the sealing compound 27 is positioned along only the seaming panel radius 26 and an adjacent portion of the seaming panel 24. It has been found that an excess amount of the sealing material 27 will prevent the proper formation of the desired double seam.

Reference is now made to FIGURE 2 wherein there is illustrated the apparatus utilized in closing the can body 10 with the end unit 18. This apparatus includes a mold, which is generally referred to by the numeral 28. The mold 28 includes a bottom wall 29 and an upstanding side wall 30, the walls 29 and 30 defining a cavity adapted to snugly receive the can body 10 when filled with a product. However, the cavity of the mold 28 is such as to permit the ready insertion of the can body 10 therein when empty. At this time it is pointed out that because of their large irregularly shaped circumference, the empty can bodies 10 tend to become badly distorted in shipping and handling. When the can bodies 10 are placed in the mold 28, they are automatically straightened to a relatively great degree. However, as is shown in FIGURE 3, there normally will be a slight spacing between the body wall 12 and the upstanding wall 30 of the mold 28.

The upstanding wall 30 of the mold 28 terminates at its upper end in a rounded supporting surface 31 adjacent the inner surface of the upstanding wall 30. Generally, the curvature of the supporting surface 31 is complementary to that of the seat 16. It is to be understood that the walls of the plastic body fit into the walls of the support mold with to .010 inch clearance on a side. The top of the mold wall extends upward to the shoulder portion 15 of the body wall with 0 to .025 inch clearance between the supporting surface 31 and the seat 16.

When the can body is to be filled with a ham, a precut whole ham is placed in the can body and the filled container is then set in a mold 28. The moldand container are then fed into a vacuum ham press (not shown) where the ham is firmly pressed into the can body 10 and air pockets within the can body are evacuated. The filled can body and mold are then fed into a vacuum closing machine (of which only portions are shown) and the metal end unit 18 is applied thereto therein. The closing machine includes a support 32 on which a mold 28 is seated. The support 32 is carried by a vertically removable shaft 33. At this time, it is pointed out that the bottom wall 29 of the mold 28 is provided with vent openings 34 therein to facilitate the escape of air from the mold when the can body 10 is seated therein. It may be desirable to pro- Referring now to FIGURES 4 through 7, the method of applying the end unit 18 to the can body 10 will be briefly described. After the end unit 18 is seated on the can body 10, the support 32 is moved upwardly to bring the end unit 18 into engagement with the seaming chuck 36. This initial engagement is illustrated in FIGURE 4. As the support 32 moves upwardly under further pressure, which may, for example, apply a total load of 450 pounds on the bottom of the mold 28, the chuck wall radius 23 moves down into engagement with the intermediate shoulder and the intermediate shoulder 15 is, in turn, moved into engagement with the mold 28 with the seat 16 of 36 particularly configurated for cooperation with the end the shoulder 15 seating on the supporting surface 31 of the upstanding mold wall 30.

The end unit 18 is now firmly supported by the can body 10 and ready for the double seaming operation.

In order to form a satisfactory double seam between the metal end unit 18 and the plastic can body 10, care must be taken to set the first operation tightness so that the hook 40 of the end unit is rolled inward and upward until it is virtually parallel to the 'body wall 12, as is shown in FIGURE 6. The second operation of the closing machine is set tight enough so that the body wall thickness in the cross section of the double seam is approximately 30% to 50% less than its original thickness, as is shown in FIGURE 7. The completed double seam is generally identified by the numeral 41 and is of a construction so as to provide a tight sealed joint between the end unit 18 and the body wall 12 with the seal being assured by means of the sealing compound 27. At this time, it is pointed out that inasmuch as the body wall 12 is formed of plastic, its resistance to flow is only slightly greater than that of the sealing compound 27 and therefore, an excess amount of the sealing compound applied to the end unit 18 would result in an improper securement of the end unit to the body wall 12. It is for this reason that the placement of the sealing compound 27 is critical.

Although only a preferred embodiment of the can and the apparatus for closing the same has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the can construction without departing from the spirit of the invention.

I claim:

1. In a can construction, a molded one-piece can body including a bottom wall, an upstanding body wall and an open upper end adapted to be closed by a metal end unit, said body wall including an upper seam forming portion, said seam forming portion being radially outwardly offset from the next adjacent portion of said body wall and there being an intermediate shoulder disposed between said seam forming portion and said next adjacent portion of said body wall, and said intermediate shoulder having an inner upwardly facing surface defining support means for supporting an end unit.

2. The can body of claim 1 wherein said intermediate shoulder also has an outer downwardly facing surface defining body wall supporting means for engaging a supporting surface and preventing endwise collapsing of said body wall during a seaming operation.

3. The can body of claim 2 wherein said can body is formed of a flexible plastic material and subject to deformation under load.

4. The can body of claim 1 wherein all of said upper seam forming portion is of a lesser thickness than said next adjacent body wall portion to facilitate the necessary folding thereof during a seaming operation.

5. The can body of claim 1 wherein all of said upper seam forming portion is of a lesser thickness than said next adjacent body wall portion to facilitate the necessary folding thereof during a seaming operation, and said intermediate shoulder tapers in thickness therebetween.

6. The can construction of claim 1 wherein said can body upper end is closed by a metal end unit secured to said can body by a double seam, said end unit having a chuck wall radius resting on said inner upwardly facing surface of said intermediate shoulder.

7. The can construction of claim 1 wherein said can body upper end is closed by a metal end unit secured to said can body by a double seam, said end unit having a 5 hook and a chuck wall forming parts of said double seam, said seam forming portion including a body flange interlocked with said hook, and a part of said seam forming portion being clamped between said hook and said chuck wall and reduced in thickness thereby.

8. The can construction of claim 7 wherein the reduction is between 30% and 50% p 9. The can construction of claim 1 wherein said can body upper end is closed by a metal end unit secured to said can body by a double seam, said end unit having an References Cited UNITED STATES PATENTS,

9/ 1967 Schild et al. 220-67 2/1968 Baker 220-67 DAVID M. BOCKENEK, Primary Examiner US. Cl. X.R.

Disclaimer and Dedication 3,491,936.-James F. Fwv, Chicago, Ill. PLASTIC CAN WITH METAL END. Patent dated Jan. 27, 1970. Disclaimer and dedication filed Mar. 24, 1971 by the assignee, Continental Can Company, I no. Hereby disclaims and dedicates to the Public claims 1, 2, 3, 6, 9 and 10 of said patent.

[Official Gazette Jwne 8, 1.971.] 

